System and method for loading/unloading containers

ABSTRACT

A container handling system and method for a wheeled transport vehicle is disclosed that is capable of loading and unloading large containers using both a hook lift and cable winch mechanisms.

RELATED APPLICATIONS

This application is a continuation-in-part application of U.S. Ser. No.10/767,594, filed Jan. 28, 2004.

FIELD OF THE INVENTION

This invention relates to a container handling system for a vehicle,more specifically it relates to a system and method for loading andunloading large containers from and onto wheeled vehicles, includingemptying the contents of such containers.

BACKGROUND OF THE INVENTION

The art typically refers to systems for loading and unloading containersas “hook lifts.” These systems have been extensively employed for thetransport of various materials within the container. In the usual case,the container may be loaded or unloaded upon the bed of the truck orvehicle utilizing the hook lift system. One very typical and frequentuse for such systems is in the picking up and hauling of refuse. An opentop or closed top container may be delivered to a point of use and thehook lift used to deploy the container, which contains a lift bar,A-frame or other similar connection to engage the hook, on the terrainunderlying the truck where it is left to be filled with refuse or thelike. When the container is full, the truck returns to the point wherethe container has been deposited and through the use of the hook liftsystem, elevates the filled container onto the truck where it may betransported, along with its contents, to a location where the containeris unloaded and emptied, like a landfill or other facility. Examples ofhook lift systems are found in U.S. Pat. Nos. 6,558,104; 5,601,393;4,350,469; 3,874,537; 3,964,625; and 4,204,793.

In addition to hook lifts, the art is familiar with cable hoist systemswhich accomplish the same loading and unloading function of the hooklift systems but use a cable winch system as described in U.S. Pat. No.5,460,473. In this type of a system two hydraulic cylinders aretypically used to move the cable about a fixed sheave attached to thefront end of the vehicle hoist frame. In the fully retracted positionthe cable, which is wrapped around sheaves connected to the cylinders,is at its longest affective length and can be connected to the front endof a container located on the ground. As the cylinders extend, theeffective length of the cable continuously shortens as it wraps aroundeach of the two cylinder sheaves and then finally around the sheaveattached at the front end of the hoist frame. As the effective length ofthe cable gets shorter, the container is pulled up and onto the vehicle,which is usually in a tilted position to facilitate loading andunloading of the container. Another more limited and specific type oflift mechanism is found in U.S. Pat. No. 3,130,847 that uses a baildevice mounted on a reciprocating carriage assembly. The bail engages aplurality of specifically designed hook bars located and space along theunderneath portion of the container. As the carriage is reciprocatedback and forth along a short path at the back end of the hoist frame thesuccessive reciprocation causes the bail to engage the next hook barsand causing the container to move forward a short distance. Thereciprocation of carriage eventually pulls the container onto the hoistframe in a slow stepwise fashion. One major problem with all theseexisting systems for loading and unloading containers is that they eachcontain only one type of mechanism to pick-up a specific type ofcontainer. For example, in the case of the hook lift it can only pick upcontainers designed specifically to accept the hook and likewise, thecable winch system can only pick up containers designed for cable basedsystems. Thus, companies must at a minimum maintain and operate twotypes of vehicles, those with hook lifts and those with cable winches. Aneed therefore exists for a universal type of loading and unloadingsystem that can load, transport, and unload all types of containers,including, but not limited to those containers specifically designed forconventional cable hoists or hook lifts. In other words, there is a needfor a system that has both a hook lift and a cable winch that can beused interchangeably depending on the many various designs of containersor other structures that require loading, transportation and unloading.

Our invention solves this problem by using a sliding carriage designthat transverses the entire length of an elongated body to allowmultiple types of container and structure designs to be loaded,transported on a wheeled vehicle and unloaded.

SUMMARY OF THE INVENTION

It is the principle object of our invention to provide an improvedsystem for loading and unloading containers and/or structures regardlessof the design of container and/or structure, more specifically whetheror not a container is designed as a hook lift or cable winch container.

Another object of our invention is to provide a system for attachment toa wheeled vehicle that allows an operator of the vehicle to servicemultiple types of container/structure without mechanical modification ofthe system prior to servicing the particular container/structure design.

One particular embodiment of our invention includes an elongated bodythat is attached to the wheeled vehicle's frame. The elongated body hasa carriage that can slide the length of the body and is driven by acentral hydraulic cylinder, such that when the cylinder is fullyextended the carriage is positioned near the front end of the elongatedbody. By “front” or “front end” we mean generally a position that istowards the front or closest to the cab and engine of the vehicle, i.e.a position that is more towards the front than the middle. Likewise,when the cylinder is fully retracted the carriage is positioned at therear or opposite end of the elongated body. Again, by “rear” or “rearend” we mean generally a position more towards the back end of thewheeled vehicle, i.e. more towards the back than the middle. This wouldrequire that one end of the central cylinder to be fixed at the rear endof the elongated body with the other end fixed to the carriage. The endof this cylinder that is fixed to the carriage can be the base or rodend of the cylinder. Alternatively, the central cylinder could have oneend fixed to the front end of the elongated body and the other end tothe carriage. In this configuration, when the cylinder is fullyretracted the carriage is positioned at the front of the elongated body.

The elongated body is pivotally connected to the vehicle frame near therear end of the frame. One or more hydraulic cylinders is pivotallyattached to a support member located on the front portion of the vehicleframe and to the elongated body near the front end such that when thecylinder is fully retracted the elongated body is in a horizontalposition parallel to and adjacent to the vehicle frame. When thiscylinder begins to extend the front end of the elongated body movesupward in an arcuate path while the rear most end of the body movesdownward. The pivot point being the connection between the vehicle frameand the elongated body located in the rear portion of the body. Raisingthe front end of the body while lowering the rear end facilitatesloading and unloading the container. The body may also contain a numberof rollers or other friction reducing surfaces positioned along thelength of the body which also makes loading and unloading easier byreducing the friction between the container bottom and the body.

As mentioned, the carriage is slidably connected to the elongated bodyand can move along the body from front to rear along a track usingbearing shoes or other friction reducing mechanism, such as rollers. Thecarriage contains the means or mechanism that connects to the containerallowing the container to be pulled up and onto the elongated body. Thismechanism may be a cable and sheave combination or a jib and hook deviceor a combination of both. If the carriage contains the jib and hookdevice, it will also contain at least one hydraulic cylinder that iscapable of moving the jib and hook device through an arcuate path suchthat when the elongated body is in an elevated position the hook canengage an A-frame on a container, a ring, a trunion, lift bar, or othersimilar connector on the container. This will be more fully understoodwith reference to the figures and the description of a preferredembodiment described below.

Once the hook has captured or engaged the container, the cylinder(s) areextended to move the jib and hook device to its original starting point.Alternatively, depending on the orientation of these cylinders, they canbe retracted to move the jib and hook device to its original startingpoint. The central hydraulic cylinder connected to the carriage is thenoperated (either retracting or extending depending on the configuration)to move the carriage from the rear of the elongated body to the frontend and in so doing pulling the container along with it until thecontainer is fully positioned on the elongated body. The cylinder(s)that elevated the elongated body is then retracted lowering the frontportion of the body until it is in a horizontal or starting positionparallel to the frame of the vehicle. However, it is within the scope ofour invention that each of the hydraulic cylinders can be operatedsimultaneously. In other words, the elongated body can be moved at thesame time as the sliding carriage and the hook and jib mechanism.

When the cable and sheave combination is used on the carriage, one endof the cable is fixedly attached preferably to the rear end of theelongated body. Alternatively, the fixed end of the cable can beattached to a cross member on the elongated body located in the rearportion of the body, or attached to the central cylinder in the rearportion of the body. The other free end of the cable is passed around asheave that is fixed to the carriage. When the carriage is positioned atthe rear of the elongated body, the free end of the cable is ofsufficient length that it can be attached to a container designed to beused with a traditional cable winch system. The free end of the cablemay contain a hook, latch, clasp or other suitable device to allow it tobe removably connected to the container. Once the cable is connected tothe container, the vehicle operator operates the central hydrauliccylinder causing the carriage to move to the front end of the elongatedbody. As the carriage moves forward so does the cable sheave which inturn reduces the length of the free end of the cable and thus pulls thecontainer onto the elongated body. Because the cable is attached to therear end of the body and is of a fixed length, when the carriage reachesthe front of the elongated body the container is necessarily pulled allthe way onto the body. Once the carriage is positioned to the front ofthe body and the container is fully on the body, then the cylinder(s)that lift the body is retracted, lowering the body and container to ahorizontal or starting position. Again, there is no requirement thateach cylinder or set of cylinders be operated in serial fashion and itis well within the scope of our invention that the cylinders may beoperated simultaneously. When loading and unloading containers with thecable and sheave combination it is preferably, but not necessary, thatthe jib and hook remain in the upright and stowed position. Furtherdetails of the components and operation of the system will be evidentfrom the following description of a preferred embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top view of the loading and unloading system of ourinvention.

FIG. 2 is a side view of the system of our invention with the carriagein the forward position.

FIG. 3 is a side view of our invention connected to a wheeled vehiclewhere the slidable carriage in the rear position.

FIG. 4 is a side view of our invention connected to a wheeled vehiclewhere the jib and hook device is connected to a container.

FIG. 5 is a side view of our invention using the jib and hook device andwith the elongated body elevated at the front end to facilitate loadingof the container.

FIG. 6 is a side view of our invention with the elongated body elevatedusing the cable and sheave combination to load a container.

FIG. 7 is a side view of our invention showing the cable and sheavecombination loading a container onto a partially elevated elongatedbody.

FIG. 8 is a side view of our invention showing the hook and jib devicebeing used to load a container onto a partially elevated elongated body.

FIG. 9 is a side view of our invention using the jib and hook deviceshowing a container fully loaded and with the carriage at the frontposition.

FIG. 10 is a side view of bur invention using the cable and sheavecombination and showing a container fully loaded and with the carriageat the front position.

FIG. 11 is a perspective view of our invention showing the slidablecarriage containing the jib and hook device and the central cylinder.

FIG. 12 is a perspective view of the slidable carriage of our invention.

FIG. 13 is a side view of our invention showing one method to transfer acontainer to a trailer.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Illustrated in FIGS. 1 through 11 are top, side and perspective views,respectively, of system 10 of our invention shown alone and as removablyattached to a wheeled vehicle frame 22. The system of our inventionincludes, among other items, elongated body 11 with carriage 13 slidablyconnected thereto. Carriage 13 may contain one or more mechanisms thatare capable of connecting to a container for loading and unloadingpurposes. Carriage 13 slides along the entire length of elongated body11 using bearing shoes 15 and is moved by action of a central hydrauliccylinder 12, which preferably is a multi-stage cylinder. As explained,central cylinder 12 is fixed at one end to carriage 13 and at the otherend to elongated body 11. As cylinder 12 retracts, carriage 13 moves indirection 50 toward the rear 40 of the body. At the fully retractedposition of cylinder 12, carriage 13 is at the rear end 40 of body 11 asillustrated in FIG. 3. As illustrated in FIG. 11, cylinder 12 issupported by a slidable cylinder support 81 that is attached to cylinder12 and is designed such that it moves along elongated body 11 whencylinder 12 is extended and retracted.

Once carriage 13 is positioned at the rear of the body the operator canuse either the jib 18 and hook 19 device or cable 20 and sheave 17combinations to engage container 35. The particular engaging mechanismwill depend on the specific design of the container. If the containerhas a lift bar 36 and is designed to be engaged by a hook lift typemechanism, then cylinders 14 on carriage 13 will be activated to raisejib 18 about pivot point 37 as shown in FIG. 4. In the raised positionhook 19 can then engage lift bar 36 on container 35. Container 35 can beelevated and lifted onto elongated body 11 in at least two ways. Thefirst is where cylinders 14 on carriage 13 are extended or retractedwhich causes container 35 to be lifted up and onto the rear end 40 ofbody 11. Once cylinders 14 are fully retracted and jib 18 is returned tothe starting position, the container will be up on the end of body 11.Carriage 13 is then moved toward front end 30 of the body by extendingcylinder 12. This will cause container 35 to move toward the front endof body 11 via travel on rollers 16 or other type of friction reducingmechanism or bearing surface. When carriage 13 reaches the front end ofbody 11 the container will be fully loaded as shown in FIG. 10. Theweight distribution of the loaded vehicle is important both legally andfrom a safety perspective. Because carriage 13 can be moved the lengthof elongated body 11 our invention has the ability to position a loadedcontainer anywhere along the length of the hoist, thus distributing theload in the most efficient manner. This is accomplished by the movementof carriage 13. FIG. 9 illustrates a loaded container 35. This containermay be position further forward 51 or rearward 50 as container 35 isreleasable engaged to carriage 13 and the movement of carriage 13 iscontrolled by extension and or retraction of multi-stage cylinder 12.

Alternatively, the container can be loaded by tilting body 11 as shownin FIGS. 5 and 6. Tilting body 11 is accomplished by extending hydrauliccylinder 24, which typically has a companion cylinder located on theopposite side of the vehicle frame 22. Hook 19 can engage lift bar 36either before or after body 11 is tilted. As shown in FIG. 6, ifcontainer 35 is of the type requiring loading by a cable mechanism,cable 20 and engaging mechanism 21 is attached to container 35 whilebody 11 is in the tilted position. Once the cable (or hook) is attachedto container 35, carriage 13 is moved by central cylinder 12 as shown inFIGS. 7 and 8 in direction 51 towards front end 30. As carriage 13 movestowards front end 30, cable 20 is pulled around sheave 17 such that thedistance between container 35 and jib 18 continuously decreases untilthe container and the jib are adjacent to each as shown in FIG. 10. Atthis point the container is fully loaded onto body 11. If the carriagewas moved forward while body 11 was in a tilted position, then cylinder24 would then be retracted to bring body 11 and container 35 to ahorizontal position parallel with vehicle frame 22 as shown in FIG. 9.

Another embodiment of our invention involves the inclusion of a traileror other wheeled vehicle in addition to the transport vehicle that isdesigned or configured to receive a container or other structuredirectly from the elongated body of the system previously described.Such a trailer is sometimes referred to as a pup trailer, however, theparticular design is not important to our invention as long as theadditional trailer or flatbed is designed or configured to allow it toreceive the container or other structure directly from the elongatedbody. Some of the benefits of using one or more additional trailers orother wheeled vehicles that can accept transfer of the container is asfollows: 1) the containers can be transported from location to locationwithout solely using the transport vehicle; 2) containers can be loadedon the trailers at a dispatch or storage location and then transportedto another location where they are unloaded; and 3) multiple containersat a given location can be loaded onto trailers using one or moretransport vehicles and then be transported to another location. Thisbenefit allows the transport vehicle having the elongated body to remainat a given site to pick up and transfer other containers directly ontotrailers or other wheeled vehicles for transport from the site.Depending on the size of the containers, it is desirable to employtrailers that can transport one or more containers. Prior art loadingand unloading systems, especially those employing only a cable hoist canonly pick up containers configured for a cable attachment, i.e. they cannot pick up containers designed to be picked up with a hook & jibengaging mechanism. In addition, those cable hoist only systems can noteasily transfer containers directly to a trailer because they have nomeans to push the container directly onto the trailer readily. Likewise,prior art systems having only a fixed hook & jib design suffer from thesame problems as the cable hoist design, that being they can only pickup containers that are specifically designed to be picked up with thattype of engagement mechanism, i.e. they can not pick up a containerdesigned to be picked up with a cable hoist. Also, with the prior arthook & jib design, there is no way to transfer a container to a trailerwhile keeping the container in a substantially horizontal position. Thismeans the container must be elevated on one end which increases thechance that the contents will spill.

The transport vehicle of our invention does not suffer from thesedeficiencies because not only can it be used to pick up multiple typesof containers, it can also use the sliding carriage to transfer thecontainer directly onto a trailer or other wheeled vehicle whilemaintaining the container in a substantially horizontal plane. Once acontainer or other structure has been loaded onto the elongated body ofour invention, the elongated body/transport vehicle's rear end isaligned with the trailer or other wheeled vehicle. FIG. 13 illustrates acontainer being unloaded from elongated body 11 of our invention onto atrailer 70. With the elongated body in a horizontal or substantiallyhorizontal position, the central hydraulic cylinder is then retractedcausing the carriage to move towards the rear of the elongated body.Front hold downs 71, as shown in FIGS. 11 and 13, or other bearingsurfaces make contact with container 35 causing it to slide or movetowards the trailer in the direction indicated as 72. Rollers, railsand/or other bearing surfaces (not shown) on container 35 engage a trackor other bearing surface on trailer 70. The central cylinder isretracted until the container is positioned partially or fully onto thetrailer. Whether or not the container is completely pushed onto thetrailer depends on a variety of factors, including, but not limited to,the size of the container and/or the trailer, the dimensions of theengaging means, and the proximity of the trailer to the elongated body.However, if the container is only partially on the trailer when thecentral cylinder is fully retracted, then the engaging means can be usedto complete loading of the container onto the trailer. The engagingmeans can be employed in a variety of ways, two of which will bedescribe here. The first involves rotating the engaging means ormechanism towards the rear of the elongated body so that it makescontact with the container. This would be performed once the carriagehas traveled as far back as possible. As the engaging mechanism rotatestowards a horizontal position it pushes the container onto the trailer.

Another approach is to reverse the direction of the carriage to move itforward until there is enough room to rotate the engaging means to ahorizontal or substantially horizontal position without contacting thecontainer. Once the engaging mechanism is positioned, the carriage isagain moved towards the rear of the elongated body using the centralcylinder until the engaging mechanism contacts and begins to push thecontainer onto the trailer. The carriage is moved rearward until thecontainer is fully positioned on the trailer. Once the container hasbeen loaded on the trailer, the elongated body is now free to be used tocollect another container.

Yet a third approach to loading container 35 onto a pup trailer involvesthe tilting elongated body 11 using cylinders 24. In loading thecontainer using this approach, first the carriage is moved rearward withjib 18 in the vertical position as far as possible pushing the containerpartially onto the trailer 70. Cylinders 24 are then extended raisingthe front end of elongated body 11 and causing the container to slidefurther onto the pup trailer 70. When elongated body 11 is tilted as faras possible, jib 18 can be rotated toward the rear, if necessary, tofurther push the container fully onto trailer 70. Likewise, in somecases it might be necessary to move the vehicle that the elongated bodyis attached in reverse to push the container onto the trailer. Once thecontainer is fully loaded onto trailer 70, then the elongated body isreturned to a horizontal position. Of course, one skilled in the artwill understand that a combination of the above-described loadingtechniques, including simultaneous operation of the hydraulic cylinders,may be employed depending on the size and shape of the container and thedesign of trailer 70.

Another benefit of our invention is the ability to dislodge the contentsof the container using central cylinder 12. In some situations, thecontainer is loaded with material that becomes lodged in the containerafter loading and transportation to a dump site. In these circumstancesmerely tilting the elongated body to elevate the front end of thecontainer will be not be sufficient to cause the contents of thecontainer to fall out of the rear end of the container into the dumpsite. Indeed, the customary method to empty a container using existinghoist devices is limited to raising the elongated body to thepredetermined dump angle and then moving the vehicle in reverse andhaving the driver repeatedly apply the vehicles brakes rapidly to causea rapid deceleration. Unfortunately, this prior method of emptyingcontainers causes excessive wear on the vehicle and hoist mechanismresulting in damaged parts and increased frequency of maintenance,especially to the vehicle's drive line and rear end differential. Ourinvention, because of the design of the central cylinder 12 avoids theseproblems and provides a safer method of emptying lodged loads from thecontainer. Loads that are difficult to empty from open top containersinclude, sludge materials, frozen granular materials and constructiondebris which may bridge across the container width. In the case ofclosed top containers, these are commonly used to receive material froma compaction device. Loaded materials are densified as a result of thecompaction forces exerted, thus the newly densified material in theclosed container often have great expansion forces which can “lock” thematerial into the container. Freezing winter conditions greatly magnifythis effect. Because the traditional method of backing up and rapidbraking does not dislodged the contents it becomes necessary to dig outthe container with a mechanical device, such as a back-hoe or similardevice, which takes time, costs money and ties up equipment. Further,the roll off hoist and loaded container must leave the emptying area togo to a safe solid footing area before this alternative emptying methodcan be performed.

Our invention provides a method of rapidly moving only the container,and not the vehicle or the elongated body, while the container is in atilted position on the elongated body. The front of the elongated body11 is elevated to a predetermined dump angle, similar to the angle shownin FIGS. 5 & 6, by extending hydraulic cylinders 24. Carriage 13, whichis slidably connected to the elongated body 11 and indirectly connectedto container 35 through an engaging means, can move forward andbackwards along the elongated body by actuating central cylinder 12.Repeated movement of the container back and forth along the dump angleof the elongated body using movement of carriage 13 creates a shakingaction similar to shaking salt out of a salt shaker. This shaking actionis only possible because of the design of the central cylinder where thesmallest diameter stage 80 (see FIG. 11) of multi-stage hydrauliccylinder 12 is the first stage to retract when multi-stage cylinder isfully extended. Rapid movement of the cylinder will result with thesystem hydraulic fluid flowing through the smallest diameter section 80of the multi-stage cylinder 12. We have found that the shaking motion ismost effective when the engaging means is a cable and cable sheavecombination because when the carriage retracts two feet of cable will bereleased per foot of travel of the carriage, thus further intensifyingthe shaking action. This occurs because cable sheave 17 is attached tocarriage 13 and moves rearward 50 with the carriage and the fixed lengthcable 20 moves across sheave 17.

Although the invention has been described with respect to preferredembodiments, it is to be also understood that it is not to be so limitedsince changes and modifications can be made therein which are within thefull scope of this invention as detailed by the following claims.

1. A method for loading or unloading a container from a transportvehicle to a trailer or other wheeled vehicle comprising, incombination, a. providing an elongated body removably attached to atransport vehicle, where the elongated body has a front and rear, acarriage, with at least one bearing surface, slidably attached to theelongated body, and a multi-stage central hydraulic cylinder connectedto the carriage and having a fixed end and a moving end, where thecarriage is substantially rectangular in shape and adapted to remain ina linear plane defined by the elongated body; b. providing a containerhaving a front end positioned on the elongated body and in bearingcontact with the bearing surface on the carriage, where the carriagemoves along the entire length of the elongated body when the centralhydraulic cylinder is extended and retracted; c. positioning andaligning the transport vehicle with a trailer or other wheeled surface;d. sliding the container onto the trailer or other wheeled vehicle byretracting the central hydraulic cylinder so that the carriage movestowards the rear of the elongated body while the bearing surface pusheson the front end of the container causing it to at least partially moveonto the trailer or other wheeled device; and e. rotating an engagingmeans pivotally attached to the carriage towards the rear of theelongated body, whereby the engaging means comes into bearing contactwith the container causing the container to slide in a rearwarddirection along the elongated body.
 2. The method of claim 1 furthercomprising rotating the engaging means after the carriage has traveledto the rear of elongated body when the central cylinder is fullyretracted.
 3. The method of claim 1 further comprising pushing thecontainer completely onto the trailer or other wheeled vehicle byrotating the engaging means.
 4. The method of claim 1 further comprisingraising the front of elongated body causing the engaging means to pushthe container onto the trailer or other wheeled vehicle.
 5. A method forunloading material in a container comprising, in combination, a.providing an elongated body removably attached to a transport vehicle,where the elongated body has a length defined by a front locatedadjacent to a transport vehicle cab and a rear located opposite thefront, a carriage, with at least one bearing surface, slidably attachedto the elongated body, and a multi-stage central hydraulic cylinderconnected to the carriage, longitudinally extendable along the length ofthe elongated body, and having a fixed end and a moving end, where thecarriage is substantially rectangular in shape and adapted to remain ina linear plane defined by the elongated body; b. providing a containerhaving a front end, a back end, and a bottom, that is loaded withmaterial positioned on the elongated body and in bearing contact at thefront end and not the bottom with the bearing surface of the carriage;c. positioning the transport vehicle adjacent a dump site; d. elevatingthe front of the elongated body; and e. actuating the central hydrauliccylinder causing the carriage and container to move longitudinallyforward and backward along a portion of the length of the elevatedelongated member imparting a shaking action to the container and causingthe material in the container to be unloaded at the dump site out of theback end.
 6. A system for loading or unloading a container from atransport vehicle comprising, in combination, a. an elongated bodyremovably attached to a transport vehicle, where the elongated body hasan outside and a length defined by a front located adjacent to atransport vehicle cab and a rear located opposite the front; b. acarriage slidably attached to the outside of the elongated body thattravels from the rear to the front of the elongated body during loadingof a container onto the transport vehicle, where the carriage issubstantially rectangular in shape and adapted to remain in a linearplane defined by the elongated body; c. a multi-stage central hydrauliccylinder having a fixed end and a moving end, where the fixed end isattached to the rear of the elongated body and the moving end isattached to the carriage such that extending and retracting the centralhydraulic cylinder moves the carriage from the rear of the elongatedbody to the front of the elongated body and necessarily causes thecontainer attached to the engaging means to be loaded onto the elongatedbody; d. means for releasably engaging a container, where the engagingmeans is connected to and moves with the carriage along the entirelength of the elongated body when the central hydraulic cylinder isextended or retracted; and e. a slidable cylinder support not connectedto the carriage and attached to at least one stage of the centralhydraulic cylinder where the slidable cylinder support is configured tomove independently of the carriage and only when the at least one stagemoves, to support the central hydraulic cylinder, and to move along theelongated member during extension and retraction of the centralhydraulic cylinder.